Question

A body is sliding down an inclined plane having coefficient of friction 0.5. If the normal reaction is twice that of the resultant downward force along the incline, the angle between the inclined plane and the horizontal is

• A. 15^o
• B. 30 ^o
• C. 45 ^o
• D. 60 ^o

Answer 1

Answer: (C)

45 ^o

Answer 2

Resultant downward force along the incline

$= m g ( \sin \theta - \mu \cos \theta )$

Normal reaction $= m g \cos \theta$

Given : $m g \cos \theta = 2 m g ( \sin \theta - \mu \cos \theta )$

By solving $\theta = 45 ^ { \circ }$ .